Process for preparing stable organic hydroxysulfide compositions

ABSTRACT

An improved process is provided for reacting starting materials in the presence of an acid catalyst in a reaction zone to produce an acid sensitive product. The starting materials are circulated in the reaction zone through a fixed bed of solid acid-type ion exchange resin to thereby catalyze the reaction, and the resulting reaction product is withdrawn from the reaction zone. Starting materials comprised a mercaptan and an aldehyde or ketone are reacted in accordance with the process to produce high yields of aliphatic hydroxyalkyl or hydroxyaryl sulfide.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to organic hydroxysulfidecompositions and an improved process for preparing such compositions.

2. Description of the Prior Art

The acid catalyzed reaction of formaldehyde with mercaptans (aliphaticthiols) to produce aliphatic hydroxymethyl sulfide compositions has beenknown heretofore. However, the hydroxymethylated compositions producedhave been unstable and are sensitive to acid. In general, when startingmaterials are reacted in the presence of an acid catalyst to produceacid sensitive products such as aliphatic alphahydroxyalkyl orhydroxyaryl sulfides, the products are subject to degradation as aresult of prolonged contact with the acid catalyst, and problems inseparating the acid catalyst from the product are often encountered, allof which results in low yields. Thus, there is a need for an improvedprocess for preparing an acid sensitive product by reacting startingmaterials in the presence of an acid catalyst.

By the present invention such an improved process for producing acidcatalyzed products which are acid sensitive is provided whereby highproduct yields can be obtained. Further, an improved process forreacting mercaptans with aldehydes or ketones in the presence of an acidcatalyst to produce stable aliphatic hydroxyalkyl or hydroxyarylsulfides is provided. Also, the present invention provides a novel andstable dodecyl hydroxymethyl sulfide composition.

SUMMARY OF THE INVENTION

A process for reacting starting materials in the presence of an acidcatalyst in a reaction zone to produce an acid sensitive product isprovided. The process comprises circulating the starting materials inthe reaction zone through a fixed bed of solid acid-type ion exchangeresin to thereby catalyze the reaction and then withdrawing theresultant reaction product from the reaction zone.

In another aspect, an improved process for producing aliphatichydroxyalkyl or hydroxyaryl sulfides is provided. The process comprisesthe steps of charging starting materials to a reaction zone comprised ofa mercaptan and an aldehyde or ketone, circulating the resultant mixtureof the starting materials in the reaction zone through a fixed bed ofsolid acid-type ion exchange resin catalyst whereby the mixturecatalytically reacts to form an aliphatic hydroxyalkyl or hydroxyarylsulfide composition and withdrawing the produced composition from thereaction zone.

When the aldehyde or ketone starting material is dissolved in water, theprocess includes the additional steps of combining a solvent for theproduced composition with the starting materials which forms anazeotropic mixture with water, heating the resulting starting materialmixture during the reaction to vaporize the azeotropic mixture formed bythe water and the solvent, withdrawing the vaporized azeotropic mixturefrom the reaction zone, condensing the vaporized azeotropic mixture,separating the condensed azeotropic mixture into condensed water andcondensed solvent components, withdrawing the condensed water componentand returning the condensed solvent component to the reaction zone. Theproduced aliphatic hydroxyalkyl or hydroxyaryl sulfide composition andsolvent are withdrawn from the reaction zone and separated whereby thecomposition is recovered.

In yet another aspect of the present invention, a novel dodecylhydroxymethyl sulfide composition (CH₃ (CH₂)₁₁ SCH₂ OH) is provided.

It is, therefore, a general object of the present invention to providean improved process for reacting starting materials in the presence ofan acid catalyst to produce an acid sensitive product.

A further object of the present invention is the provision of a processfor producing organic hydroxysulfide compositions, and particularly,aliphatic hydroxyalkyl or hydroxyaryl sulfide compositions.

Other objects, features and advantages of the present invention will bereadily apparent to those skilled in the art upon a reading of thedescription of preferred embodiments which follows when taken inconjunction with the accompanying drawing.

DESCRIPTION OF THE DRAWING

In the accompanying drawing forming a part of this disclosure, a systemof apparatus which can be utilized for carrying out the improved processof the present invention is illustrated schematically.

DESCRIPTION OF PREFERRED EMBODIMENTS

In accordance with the present invention an improved process forreacting starting materials in the presence of an acid catalyst toproduce an acid sensitive product is provided. The starting materialsare charged to a reaction zone and are circulated within the reactionzone through a fixed bed of solid acid-type ion exchange resin catalyst.The acid-type ion exchange resin catalyzes the reaction between thestarting materials to produce the desired acid sensitive product, andthe product is withdrawn from the reaction zone and from the acid-typeion exchange resin catalyst prior to when degradation of the productoccurs. By carefully controlling the contact of the acid sensitiveproduct with the acid catalyst and avoiding catalyst-product separationproblems, high yields of product are realized.

In a more specific aspect of the present invention, an improved processfor producing aliphatic hydroxyalkyl or hydroxyaryl sulfides isprovided. In accordance with the process, starting materials comprisedof a mercaptan and an aldehyde or ketone are charged to a reaction zone.While within the reaction zone, the starting materials are circulatedthrough a fixed bed of solid acid-type ion exchange resin catalyst for atime sufficient for the starting materials to react and form analiphatic hydroxyalkyl or hydroxyaryl sulfide composition. When thereaction has gone to completion and before the acid sensitive productcomposition is degraded by contact with the acid catalyst, the productcomposition is withdrawn from the reaction zone.

When the aldehyde or ketone utilized is dissolved in an aqueous solvent,e.g., an aqueous formaldehyde solution, the process includes theadditional steps of combining a solvent for the produced compositionwith the starting materials which forms an azeotropic mixture with thewater. The starting materials are heated during the reaction whereby thewater-solvent azeotropic mixture is vaporized. The vaporized azeotropicmixture is withdrawn from the reaction zone, condensed and separatedinto water and solvent components. The condensed water is withdrawn andthe solvent is recycled to the reaction zone. The product compositionand solvent are then withdrawn from the reaction zone and separatedwhereby the product composition is recovered.

A variety of commercially available solid acid-type ion exchange resinsare suitable for use in accordance with the improved process of thepresent invention. For example, solid acid-type ion exchange resins aremanufactured by the Rohm & Haas Company of Philadelphia, Pa. under thetrade designations "Amberlyst 15" and "Amberlyst XN-1010". Amberlyst 15and Amberlyst XN-1010 are both styrene divinyl benzene resins which havebeen modified by addition of a reactive acid functionality. Both arestrongly acidic macro-reticular cation exchange resins Amberlyst 15 hasless surface area but a higher ion exchange capacity than AmberlystXN-1010. Examples of other suitable resins which can be used are thosemarketed by the Rohm & Haas Company under the trade designation"Amberlite" including Amberlite 200, Amberlite 252 and others. TheAmberlite resins are also acidic styrene divinyl benzene resins, butthey require pretreatment with a strong acid while the Amberlyst resinsdo not.

Of the various solid acid-type ion exchange resins which can beutilized, the strongly acidic macro-reticular cation exchange resinswhich do not require acid pretreatment are the most preferred.

In the process of this invention for producing aliphatic hydroxyalkyl orhydroxyaryl sulfides from mercaptan and aldehyde or ketone startingmaterials, various mercaptans (also known as aliphatic thiols) can beused. Alkyl mercaptans are presently commercially available which areprepared in various ways including reacting hydrogen sulfide witholefins, alkyl halides and aklylene epoxides. Examples of suitable alkylmercaptans useful in accordance with this invention are n-decylmercaptan, n-dodecyl mercaptan, secondary and tertiary dodecylmercaptan, n-tetradecyl mercaptan, tertiary tetradecyl mercaptan, andvarious isomers of dodecyl and tetradecyl mercaptan. Generally, alkylmercaptans having from 10 to 24 carbon atoms are preferred.

The aldehydes or ketones useful in accordance with the present inventionare those represented by the formula: ##STR1## wherein R and R¹ are eachindependently hydrogen or an alkyl or aryl group having from about 1 toabout 24 carbon atoms. Examples of aldehydes falling within the abovedefinition are formaldehyde, acetaldehyde, decanal and octadecanal.Examples of ketones are dimethyl ketone methylethyl ketone, dibutylketone and n-octadecyl methyl ketone.

When a mercaptan is reacted with an aldehyde or ketone as describedabove in the presence of an acid catalyst, an aliphatic hydroxyalkyl orhydroxyaryl sulfide composition is produced represented by the formula:##STR2## wherein R₁ is an aliphatic group and R₂ and R₃ are eachindependently hydrogen or an alkyl or aryl group having from about 1 toabout 24 carbon atoms.

The process for carrying out the above described reaction in accordancewith the present invention comprises the steps of charging the mercaptanand aldehyde or ketone starting materials to a reaction zone,circulating the resultant mixture of starting materials in the reactionzone through a fixed bed of solid acid-type ion exchange resin catalystwhereby the mixture catalytically reacts to form the aliphatichydroxyalkyl or hydroxyaryl sulfide composition, and then withdrawingthe composition from the reaction zone.

A novel stable composition which can be produced utilizing the improvedprocess of the present invention is dodecyl hydroxymethyl sulfide, i.e.,CH₃ (CH₂)₁₁ SCH₂ OH. Such composition is useful as a lubricationadditive and as an intermediate in the production of other lubricationadditives and pesticides.

In producing dodecyl hydroxymethyl sulfide, n-dodecyl mercaptan, anaqueous formaldehyde solution and a hexane solvent are charged to areaction zone. While within the reaction zone, the mixture of startingmaterials is heated to vaporize the azeotropic mixture formed by thewater in the aqueous formaldehyde solution and the hexane solvent. Themixture is circulated while being heated in the reaction zone through afixed bed of solid acid-type ion exchange resin catalyst for a period oftime sufficient for the starting materials to catalytically react tocompletion whereby a high yield of dodecyl hydroxymethyl sulfide isproduced. During the reaction, the vaporized azeotropic mixture iswithdrawn from the reaction zone, condensed and separated into condensedwater and hexane components. The condensed water is withdrawn, and thecondensed hexane is returned to the reaction zone. The productcomposition, dodecyl hydroxymethyl sulfide, and hexane solvent arewithdrawn from the reaction zone and separated to recover stable dodecylhydroxymethyl sulfide. The separation of the product composition fromthe hexane solvent is conveniently carried out by vacuum evaporation ofthe hexane.

As will be understood by those skilled in the art, when the aldehyde orketone starting material is utilized in the form of an aqueous solution,solvents other than hexane can be utilized which form azeotropicmixtures with water and which dissolve the product sulfide composition.Preferred such solvents are those that vaporize at temperatures belowabout 100° C. at atmospheric pressure, e.g., propane, butane, pentane,isobutane, cyclohexane and benzene.

Referring now to the drawing, a system of apparatus which can beutilized for carrying out the improved process of the present inventionis illustrated and generally designated by the numeral 10. Included inthe system 10 is a reactor 12 to which the starting materials includingwater and azeotropic mixture forming solvent are charged by means of aconduit 14 connected thereto. A conduit 16 is connected between anoutlet at the bottom of the reactor 12 and a pump 18. The discharge ofthe pump 18 is connected by a conduit 20 to the inlet of a vessel 22containing a fixed bed of acid-type ion exchange resin catalyst. Theoutlet of the vessel 22 is connected by a conduit 24 to the inlet of aheater 26. A conduit 48 for bypassing the vessel 22 is connected to theconduits 20 and 24, and shutoff valves 52, 54 and 50 are disposed in theconduits 20, 24 and 48, respectively. A conduit 28 connected to theoutlet of the heater 26 is connected to an inlet connection in thereactor 12. A conduit 30 having a shutoff valve 32 disposed therein isconnected to the conduit 20 for withdrawing reaction product and solventfrom the system 10.

A vapor outlet at the top of the reactor 12 for withdrawing vaporizedazeotropic mixture therefrom is connected by a conduit 34 to the inletof an azeotropic mixture condenser 36. The outlet of the condenser 36 isconnected by a conduit 38 to the inlet of a separator 40. The separator40 functions to separate the condensed azeotropic mixture into condensedwater and solvent components. The solvent component is withdrawn from anoutlet in the separator 40 and returned to the reactor 12 by a conduit42 connected therebetween, and the separated water component iswithdrawn from the separator 40 by way of an outlet therein and aconduit 46 connected thereto.

In operation of the system 10, starting materials such as n-dodecylmercaptan, an aqueous formaldehyde solution and hexane are conducted tothe reactor 12 by the conduit 14. The starting material mixture iswithdrawn from the bottom of the reactor 12 by way of the conduit 16 andpumped by the pump 18 through the vessel 22 containing the fixedcatalyst bed by way of the conduit 20 and the open shutoff valve 52therein, through the heater 26 by way of the conduit 24 and open shutoffvalve 54 therein and back to the reactor 12 by way of the conduit 28. Asthe starting materials are circulated by the pump 18, they are contactedby the acid-type ion exchange resin catalyst within the vessel 22 sothat they react, and they are heated in the heater 26 whereby theazeotropic mixture formed by the water from the aqueous formaldehydesolution and the hexane solvent is continuously vaporized. The vaporizedazeotropic mixture is withdrawn from the reactor 12 by way of theconduit 34 and condensed by the condenser 36. The condensed azeotropicmixture enters the separator 40 by way of the conduit 38 and isseparated into condensed water and condensed hexane components. Thewater is removed from the bottom of the separator 40 by way of theconduit 46 and the hexane is returned to the reactor 12 by way of theconduit 44.

Thus, as the mixture of starting materials is circulated through thevessel 22 containing the fixed resin catalyst bed and through the heater26, the starting materials are caused to react and the azeotropicmixture of water and solvent is vaporized so that water is removed fromthe mixture. The circulation is continued until the reaction has gone tocompletion at which time if the water has not all been removed, thebypass shutoff valve 50 is opened and the shutoff valves 52 and 54 areclosed so that the vessel 22 and acid-type ion exchange resin thereinare bypassed and the product composition formed does not continue tocontact the catalyst and degrade. Once all of the water has been removedfrom the mixture containing the product composition, the valve 32 isopened and the product composition dissolved in the solvent is removedfrom the system 10. The product composition can then be isolated fromthe solvent, if desired, e.g., by vacuum evaporation of the solvent.

In order to further illustrate the present invention, the followingexamples are given.

EXAMPLE 1

162.2 grams of a 37% by weight aqueous solution of formaldehyde(equivalent to 2 moles) and 404 grams of n-dodecyl mercaptan (equivalentto 2 moles) were placed in a reaction pot along with 2 grams ofAmberlyst 15 acid-type ion exchange resin catalyst. The reactants andcatalyst were heated to 100° C. and allowed to react for 2 hours.Thereafter, the catalyst was removed from the reaction product byfiltration. The product composition was identified to be dodecylhydroxymethyl sulfide by gas chromatography, IR, NMR and elementalanalysis, and a yield of only 58.3% was realized.

EXAMPLE 2

162.2 grams of a 37% by weight aqueous solution of formaldehyde(equivalent to 2 moles), 404 grams of n-dodecyl mercaptan (equivalent to2 moles) and 250 milliliters of hexane were placed in a one liter flaskequipped with an overhead azeotropic mixture condenser and a condensedwater and hexane component separator. A fixed bed of Amberlyst 15acid-type ion exchange resin catalyst was provided, and the reactionmixture in the flask was circulated by a pump from the flask through thecatalyst bed and back to the flask at a rate of about 2 milliliters perminute for a time period of 4 hours. While the reaction mixture wasbeing circulated through the catalyst bed, it was heated to atemperature of approximately 100° C. whereby the azeotropic mixtureformed by the hexane and water in the flask was vaporized, withdrawnfrom the flask and condensed. The water component of the condensedazeotropic mixture was separated from the hexane component andwithdrawn, and the hexane was returned to the reaction flask. A 91.8%yield of dodecyl hydroxymethyl sulfide was realized after the hexane wasremoved by vacuum evaporation.

Thus, the present invention is well adapted to attain the ends andadvantages mentioned as well as those inherent therein. While numerouschanges in the arrangement and condition of process steps may suggestthemselves to those skilled in the art, such changes are encompassedwithin the spirit of the invention as defined by the appended claims.

What is claimed is:
 1. In a process for reacting a mercaptan with asecond reactant selected from the group consisting of aldehydes andketones in the presence of an acid catalyst in a reaction zone toproduce an acid sensitive aliphatic hydroxyalkyl or hydroxyaryl sulfideproduct, the improvement comprising:collecting said mercaptan, saidsecond reactant and sulfide product produced therefrom in a firstsection of said reaction zone, said reaction zone also having a secondsection with a fixed bed of solid acid-type ion exchange resin catalystdisposed therein; circulating the resultant mixture collected in saidfirst section through said second section so that said mercaptan andsaid second reactant catalytically react to form said sulfide product;and then withdrawing the resultant reaction product from said reactionzone.
 2. The process of claim 1 wherein said solid acid type ionexchange resin is selected from the group consisting of strongly acidicmacro-reticular cation exchange resins.
 3. The process of claim 2wherein said mercaptan is an alkyl mercaptan having from 10 to 24 carbonatoms.
 4. The process of claim 3 wherein said aldehydes and ketones arerepresented by the formula: ##STR3## wherein R and R¹ are eachindependently hydrogen or an alkyl or aryl group having from about 1 toabout 24 carbon atoms.
 5. The process of claim 3 wherein said alkylmercaptan is n-dodecyl mercaptan, said second reactant is formaldehydeand said acid sensitive product is dodecyl hydroxymethyl sulfide.
 6. Theprocess of claim 5 wherein said catalyst is a styrene divinyl benzeneresin having acid functionality.
 7. The process of claim 2 wherein saidsecond reactant is dissolved in an aqueous solvent.
 8. The process ofclaim 7 which is further characterized to include the steps of:combininga solvent for said sulfide product with said mercaptan and said secondreactant, said solvent forming an azeotropic mixture with water presentin said reaction zone; heating the contents of said reaction zone duringsaid reaction to vaporize said azeotropic mixture; withdrawing saidvaporized azeotropic mixture from said reaction zone during saidreaction; condensing said vaporized azeotropic mixture; separating thecondensed azeotropic mixture into condensed water and condensed solventcomponents; withdrawing said condensed water component; and returningsaid condensed solvent component to said reaction zone.
 9. The processof claim 8 wherein said solvent which forms an azeotropic mixture withwater is hexane.
 10. A process for producing a hydrosulfide compoundhaving the formula: ##STR4## wherein R₁ is an alkyl group from 10 to 24carbon atoms, and R₂ and R₃ are each independently hydrogen or an alkylor aryl group having from about 1 to about 24 carbon atoms comprisingthe steps of:charging starting materials to a reaction zone comprised ofan alkyl mercaptan having from 10 to 24 carbon atoms and a secondreactant having the formula: ##STR5## wherein R and R¹ are eachindependently hydrogen or an alkyl or aryl group having from about 1 toabout 24 carbon atoms; collecting said starting materials andhydroxysulfide compound produced therefrom in a first section of saidreaction zone, said reaction zone also having a second section with afixed bed of solid acid-type ion exchange resin catalyst disposedtherein; circulating the resultant mixture collected in said firstsection through said second section whereby said mercaptan and saidsecond reactant catalytically react to form said hydroxysulfidecompound; and withdrawing said hydroxysulfide compound from saidreaction zone.
 11. The process of claim 10 wherein said solid acid-typeion exchange resin is selected from the group consisting of stronglyacidic macro-reticular cation exchange resins.
 12. The process of claim11 wherein R₁ is a dodecyl group and R₂, R₃, R and R¹ are each hydrogen.13. The process of claim 10 wherein said second reactant is dissolved inwater and wherein said process is further characterized to include thesteps of:combining a solvent for said produced hydroxysulfide compoundwith said starting materials which forms an azeotropic mixture with saidwater; heating the contents of said reaction zone during said reactionto vaporize the azeotropic mixture formed by said water and saidsolvent; withdrawing said vaporized azeotropic mixture from saidreaction zone during said reaction; condensing said vaporized azeotropicmixture; separating the condensed azeotropic mixture into condensedwater and condensed solvent components; withdrawing said condensed watercomponent; and returning said condensed solvent component to saidreaction zone.
 14. A process for producing dodecyl hydroxymethyl sulfidecomprising:charging starting material to a reaction zone comprised ofn-dodecyl mercaptan, an aqueous formaldehyde solution and a hexanesolvent; collecting said starting materials and dodecyl hydroxymethylsulfide produced therefrom in a first section of said reaction zone,said reaction zone also having a second section with a fixed bed ofsolid acid-type ion exchange resin catalyst disposed therein;circulating the resultant mixture collected in said first sectionthrough said second section whereby said n-dodecyl mercaptan and saidformaldehyde catalytically react to form said dodecyl hydroxymethylsulfide; heating the contents of said reaction zone during said reactionto vaporize an azeotropic mixture by the water in said aqueousformaldehyde solution and said hexane solvent; withdrawing saidvaporized azeotropic mixture from said reaction zone during saidreaction; condensing said vaporized azeotropic mixture; separating thecondensed azeotropic mixture into condensed water and condensed hexanecomponents; withdrawing said condensed water component; returning saidcondensed hexane component to said reaction zone; withdrawing saiddodecyl hydroxymethyl sulfide and said hexane solvent from said reactionzone; and separating said dodecyl hydroxymethyl sulfide from said hexanesolvent.
 15. The process of claim 14 wherein said solid acid-type ionexchange resin catalyst is a strongly acidic macroreticular cationexchange resin.
 16. The process of claim 15 wherein said mixture isheated to a temperature of about 100° C.
 17. The process of claim 16wherein said hexane solvent is separated from said dodecyl hydroxymethylsulfide by vacuum evaporation of said hexane solvent.